Testosterone (TRT)
Mechanism
Let's be clear about what this is: a steroid hormone, not a peptide, even though it lives in every peptide conversation anyway. Exogenous testosterone steps in for what your body stopped making, binding androgen receptors to drive protein synthesis, red blood cell production, bone density, sexual function. All of it, at once.
Key Benefit
TRAVERSE trial (5,246 men): no increased cardiovascular risk. FDA removed CV black box warning Feb 2025. Improves insulin sensitivity, muscle mass, bone density (~11% spine gains in men 65+), sexual function, and energy. FDA panel Dec 2025 recommended further label liberalization.
Evidence Base
The data here is not thin: Phase 3 and Phase 4, stacks of it. TRAVERSE is the study that matters, published in NEJM in 2023, and it settled the cardiovascular safety question for good. But hear this: the FDA approval is for male hypogonadism. Not for getting older. Not for feeling tired at 50. Hypogonadism, specifically, or nothing.
Route & Rationale
IM injection, topical gel, transdermal patch, or SC pellet. Multiple delivery options. IM cypionate/enanthate every 1–2 weeks most common. Gel for daily steady-state. Choice depends on patient preference, insurance, and compliance.
Interactions
CRITICAL: Suppresses HPG axis. Reduces or eliminates sperm production. Fertility impact can be permanent. Discuss fertility preservation before starting. Causes erythrocytosis (elevated hematocrit). Requires regular CBC monitoring. May worsen sleep apnea. PSA monitoring recommended.
Regulatory Status
FDA-approved, yes, but only for male hypogonadism: confirmed low T on labs, plus symptoms, not just a number on a page you didn't like. It's a Schedule III controlled substance. WADA bans it at all times, not just on competition day, every single day of the year.
Gender Note
This entry is about TRT for male hypogonadism. Women have their own testosterone protocols: different dosing, different indications, different monitoring, not a smaller copy of the men's version. That one needs a specialist, not a guess.
Hard Contraindications
Pregnancy/planning
Cautions
Cancer (active/history)
For information and research purposes only. This is not medical advice and not a recommendation to use this substance. Discuss anything here with your healthcare provider.